aa.cpp

求前N个自然数的全排列的程序源代码。短小精悍

// aa.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <memory.h>

void
printarray (int *gbuf,int glen,int *inbuf,int n)
{
	int i;
	int *tmpbuf = NULL;

	if (!n){
		for (i = 0; i < glen; i++){
			printf ("%d ", gbuf[i]);
		}
		printf ("\n");
		return;
	}

	tmpbuf = (int*)malloc (sizeof(int)*n);
	memcpy (tmpbuf, inbuf, sizeof(int)*n);

	for (i = 0; i < n; i++){
		int t;

		t = tmpbuf[0];
		tmpbuf[0] = tmpbuf[i];
		tmpbuf[i] = t;
		gbuf[glen - n] = tmpbuf[0];

		printarray (gbuf, glen, tmpbuf + 1, n - 1);
	}

	if (tmpbuf)
		free (tmpbuf);
}

int
main (int argc,char **argv)
{
	int i;
	int *gbuf = NULL;
	int glen;

	scanf ("%d", &glen);
	
	if (glen > 0)
		gbuf = (int*)malloc(sizeof(int)*glen);
	else
		return 0;
	
	for (i = 0; i < glen; i++)
		gbuf[i] = i + 1;
	printarray (gbuf, glen, gbuf, glen);

	if (gbuf)
		free (gbuf);

	return 0;
}